Julia Roberts shines as the jealous Queen and director Tarsem Singh injects some toughness into Snow White, played by Lily Collins.

Encased in a coffin, waiting to be brought back to life: That's how Snow White spends a good portion of the folk story that bears her name. There's no such downtime for the princess in the snappy retelling "Mirror Mirror," a fractured fairy tale that occupies the divide between Disney and Grimm.

A booster shot of testosterone lends kinetic kick to director Tarsem Singh's visually inventive interpretation, without shortchanging the requisite froufrou or sugarcoating the story's dark Oedipal heart. The mash-up can be choppy, but the fable zings along on the sharp comic timing of the cast, led by a royally wicked Julia Roberts.

The screenplay by Marc Klein and Jason Keller (a screen story credit goes to Melisa Wallack) pointedly rewrites the fairy-tale convention that finds every damsel helplessly imperiled until a prince delivers her from danger. This Snow White (Lily Collins) can get gussied up with the best of them, but she also holds her own in a fencing duel. And — hello, switcheroo — she rescues a prince in distress.

When in exile, Snow (it's a first-name-informal kingdom) receives martial-arts instruction from the dwarfs. Like the famous septet from Disney's 1937 classic, this woods-dwelling crew provides collective-sidekick slapstick, and each has a character-defining shtick — most memorably the love-struck Half Pint (Mark Povinelli). But they've also been restored to their folk tale roots as bandits and outcasts. They're action antiheroes with hearts of gold.

Transforming Snow White to an action hero in her own right doesn't lessen the archetypal power of the stepmother-daughter, age-beauty conflict. Collins ("The Blind Side") is a convincing foil for Roberts' jealous Queen, personifying intelligence, innate goodness and fairest-of-them-all femininity. If a movie-star self-regard has crept into Roberts' work over the years, here she uses it to winning effect, savoring the tension and silliness, and making an exceptionally entertaining evil monarch.

Advised and chided by the alter ego who resides on the other side of her magic mirror — one of the film's more striking elements — the Queen sets her sights on an imperial merger with Prince Alcott (Armie Hammer), whose province's resources would save her from the brink of bankruptcy.

Hammer, who brought an air of wounded regality to the Winklevoss twins in "The Social Network" and Clyde Tolson in "J. Edgar," gets to shake off the aggrievement and let his princely flag fly, often without a shirt.

Singh (a.k.a. Tarsem Singh Dhandwar or simply Tarsem) is a fantasist whose singular knack for spectacle can also be his weakness, set-piece razzle-dazzle not infrequently overwhelming the characters in his previous films: "The Cell," "The Fall" and "Immortals." That weakness reveals itself in "Mirror Mirror" when he stops the story cold to indulge in a puppet sequence.

But mostly the built-in structure of a well-known tale helps to rein him in, as does the propulsive rhythm of one-liners — some of the best are delivered with panache by Nathan Lane and Robert Emms, as mouthy servants. For most of its running time, the film strikes the right balance of make-believe enchantment and snark-infused lampoon, playing to older kids and adults alike.

Crucial to the movie's magic are Tom Foden's lush and witty production design and the splendid costumes by Eiko Ishioka, the renowned designer's final screen work before her death in January. The finery and regalia of their contributions are integral to Singh's vision, giving this mostly conventional princess story its fair share of romantic froth and more than a little moxie.